Incubators have been known as instruments employed in biochemical treatment such as culturing microbes or cells, as well as observing biochemical reactions. Incubators are the housings, where objective samples of culture or test are situated, equipped with functions maintaining a habitable environment for the samples such as a temperature and a humidity in the housings. Since a large number of samples are cultured or tested under the same environment, incubators in general accommodate a large number of samples.
It is frequently desirable to monitor biochemical treatment for an extended period of time, and thus the samples must be sequentially taken out from the incubator for routines such as analysis, observation and reagent distribution, then the samples are restored into the incubator. These routines must be practiced at a given interval. An opening is thus provided to the incubator so that samples can be taken out and restored. A large opening is provided to conventional incubators because this opening is used for various applications in addition to the purpose discussed above such as locating samples in the incubator, cleaning inside thereof and maintenance work.
However, every time the opening is opened at taking out and restoring the samples, gaseous atmosphere inside the incubator flows out and the open air flows in. As a result, the environment inside the incubator such as a temperature and humidity are changed. If the environment change exceeds a maximum tolerable limit, it lowers reliability of the culture or test result.
As such, the conventional incubator has an opening, which is frequently opened and closed, large enough to change the inside environment. This has left a problem of lowering reliability of culturing or testing the samples.